Fluid-pressure-operated sensing device

ABSTRACT

In one embodiment a fluid-operated sensing device comprises a body having a blind bore extending into the body and cylindrical spigot extending coaxially within the bore from the inner end of the bore. A coaxial exhaust passage extends from a conduit in the body coaxially, through the spigot to a valve seat formed at the and of the spigot and a valve member in the form of a disc is held captive in a counterbore at the outer end of the blind bore, between the valve seat and a cover member at the outer end of the blind bore having a central orifice. Vent openings are formed through the wall of the blind bore and the disc can be moved from a position in which it is out of engagement with said seal to allow compressed air to pass from the exhaust passage out of the vent openings, to a position in which it engages the valve seat, by an air jet directed at the orifice in the cover member In another embodiment a body has an external surface with single curvature, which forms a valve seat around an exhaust passage extending from a conduit in the body to the curved surface and a valve member comprises a flexible strip which can be bent against said curved surface to close off said exhaust passage.

United States Patent [72] Inventor Francis Xavier Kay Winslow, England [21] Appl. No. 852,341 22 Filed Aug. 22, 9169 [45] Patented Sept. 14, 1971 [73] Assignee Instruments and Movements Limited London, England [54] FLUlD-PRESSURE-OPERATED SENSING DEVICE 1 Claim, 2 Drawing Figs.

[52] US. Cl 25l/6l.l, 251/303 [51] Int. Cl Fl6k 7/17 [50] Field of Search 25l/6l.l, 12, 63, 25

[56] References Cited UNITED STATES PATENTS 703,805 7/1902 Murray 251/46 X 1,014,235 1/1912 Laudet et a1 251/25 X 1,220,985 3/1917 Harter 251/61.1X 1,606,245 11/1926 Lang 251/25 2,529,028 11/1950 Landon 251/61.1 X 3,055,629 9/1962 Jurs et a1 251/25 Primary Examiner-Arnold Rosenthal 1i!t0rneyFriedman & Goodman ABSTRACT: In one embodiment a fluid-operated sensing device comprises a body having a blind bore extending into the body and cylindrical spigot extending coaxially within the bore from the inner end of the bore. A coaxial exhaust passage extends from a conduit in the body coaxially, through the spigot to a valve seat formed at the and of the spigot and a valve member in the form ofa disc is held captive in a counterbore at the outer end of the blind bore, between the valve seat and a cover member at the outer end of the blind bore having a central orifice. Vent openings are formed through the wall of the blind bore and the disc can be moved from a position in which it is out of engagement with said seal to allow compressed air to pass from the exhaust passage out of the vent openings, to a position in which it engages the valve seat, by an. air jet directed at the orifice in the cover member 1n another embodiment a body has an external surface with single curvature, which forms a valve seat around an exhaust passage extending from a conduit in the body to the curved surface and a valve member comprises a flexible strip which can be bent against said curved surface to close off said exhaust passage.

PATENT-WWW 3504.680

Inventor FRANCIS XAVIER KAY FLUlD-PRESSURE-OPERATED SENSING DEVICE This invention relates to sensing devices for producing fluidpressure signals in response to thrusts applied to the devices.

Such devices are used, for example in the textile industries in conjunction with fluid-operated logic networks known as fluidic networks exercising a supervisory or controlling function over machinery. The device may be arranged for example to respond to thrusts provided by puffs of air, and may be located on the opposite side of a gap from an air jet to determine the presence or the absence of an object in the gap according to whether the device is shielded from the jet by the object or not.

Prior devices of this kind used in conjunction with fluidic networks using compressed air as the operating fluid comprise an exponential horn to receive the puffs of air transmitted across the gap, the air from the horn being passed directly into the network. This arrangement has the disadvantage that as the industrial atmosphere in which the device is used contains large amounts of dust, this dust is taken into the fluidic network associated with the device and the network subsequently becomes clogged and ceases to function.

It is an object of the present invention to provide a sensing device in which the above disadvantage is avoided.

According to the present invention there is provided a sensing device for producing a fluid-pressure signal on detection of the application or removal of a thrust applied to the device, said device comprising a body providing a conduit adapted to be connected to a source of fluid under pressure, and an exhaust passage extending from said conduit and terminating at its end remote from the conduit in a seat adjacent a valve member movable by a thrust applied thereto, against the opposing pressure of the fluid in said passage, to a position in which it engages said seat to seal off said exhaust passage from a position in which it is out of engagement with said seal to allow fluid to escape from the conduit through said passage, and movable from the former position to the latter position on removal of said thrust, so that a change in fluid pressure in the conduit, constituting a fluid'pressure signal is produced on receipt or termination of a thrust on the valve member.

Two embodiments of the invention will now be described by way of example, with reference to the accompanying drawings wherein FIG. 1 is a longitudinal sectional view of one embodiment of a device according to the invention and FIG. 2 is a longitudinal sectional view of another embodiment of a device according to the invention.

Referring to FIG. 1 the device shown therein comprises a generally cylindrical body 1 into one end of which extends a first coaxial cylindrical bore 3 providing a conduit adapted to receive a compressed air pipe. At its inner end of said bore terminates in a first annular end face 3a. A second coaxial bore 8 extends from the other end of the body terminating in a second annular end face, a central portion of the body being defined between said annular end faces. A coaxial cylindrical spigot 9 extends from said second end face into the bore 8 and a third coaxial bore 4 of much reduced diameter with respect to the bores 3 and 8 extends through said central portion of the body from the end face 3a and for the entire length of the spigot 9 and constitutes an exhaust passage. The body 1 provides in effect an outer cylindrical wall 10 surrounding the bore 8. The free end of said spigot 9 is formed as a valve seat around the end of the exhaust passage 4 remote from the conduit 3, said valve seat being inset axially with respect to the free end of the cylindrical wall 10. The wall 10 is formed with an internal annular recess 11 defined by a coaxial counter bore at the end of the bore 8 extending from its free end to slightly beyond the axial position of the valve seat. A valve member 6 in the form of a disc is mounted loosely in said recess 11 so as to permit its axial movement between a positionin which it engages the valve seat and a position in which it is out of engagement therewith. The valve member 6 is retained by an annular cover member 7 secured to the free end of the cylindrical wall 10, the cover 7 having a central orifice 12 communicating with a concave parabolic surface on the inside of the cover member 7 which extends almost to a continuous annular seat concentric with the orifice and provided by the cover member adjacent the edge of the valve member 6. The area encompassed by said continuous annular seat 5 is greater than the area encompassed by the valve seat at the end of the passage 4. Adjacent the inner end of the bore 8 a plurality of ventholes 2 extend radially through the cylindrical wall 10.

In use the device is connected, for instance, in a circuit comprising a compressed air supply pipe extending from a control orifice to the bore 3. The control orifice is formed with a transverse intersection bore providing a tapping connected to a fluidic circuit, a diaphragm valve, a pressure gauge or manometer or the like.

Air is supplied to the orifice at a substantially constant pressure. The device is arranged on one side of a gap with the orifree 12 directed towards an air jet on the other side of the gap. When the gap between the air jet and the device is unobstructed the air issuing from the jet passes through the orifice 12 and the turbulence created in the space between the parabolic surface and the valve member 6 is sufiicient to maintain the valve member 6 in engagement with the seat on the spigot 9 against the air pressure within the bore 4. The pressure within the bore 3 and the air supply pipe is thus maintained at a relatively high level. When the space between the jet and the device is obstructed preventing the air issuing from the jet from reaching the device the valve member 6 is displaced from its valve seat by the pressure of the air within the passage 4 and air from the pressure supply pipe flows through the bore 4 and the annular recess 8, out through the exhaust apertures 2 so that the pressure within the supply pipe and hence the tapping falls providing a fluid-pressure signal to the fluidic circuit, diaphragm valve, gauge or the like. The difference in the area encompassed by the valve seat at the end of the passage 4 and the area encompassed by the seat 5 ensures that the valve member 6 will be held in engagement with its valve seat by a pressure on the side of the orifice 12, which is substantially less than the pressure in the passage 4.

Another embodiment of the invention shown in FIG. 2 comprises a body 22 provided with a cylindrical bore 24 extending from .one end to receive a compressed air supply pipe. On the exterior of the body is a face having a rear portion 25 adjacent said one end which is planar and which extends parallel with the axis of said bore and a portion 26 with a single curvature which curves gradually towards said axis the planar portion 25 being tangential to the curved portion 26. Secured to said rear portion 25 is the rear end of a flexible flat strip or whisker 21 which in its unstressed position extends generally parallel with the axis of said bore and which when bent against the body, lies closely against said curved part of said face. An exhaust passage 23 extends from the bore 24 to the curved portion of said face closely adjacent the end of the planar portion thereof.

In operation the device is connected in a circuit similar to that described with reference to FIG. I, the bore 24 being connected to the compressed air supply pipe. The device is mounted on the opposite side of a gap from an air jet with the whisker 21 extending at right angles to the direction in which air issues from the jet so that when the space between the jet and the device is unobstructed the air issuing from the jet impinges on the whisker 21 and bends it into contact with the curved portion of said face to seal off the exhaust passage 23. When the jet is obstructed by some object in the gap, the whisker returns resiliently to its straight position allowing the air to escape from the bore 24 through the passage 23 providing a fluid-pressure signal as before.

Alternatively, the whisker may be arranged so as to be deflected mechanically for example by part of a machine or by some material of even the most delicate kind such as a strand of yarn. being processed on a textile-spinning frame.

I claim:

recess and facing said valve seat, and

a valve member captively disposed in said recess between said valve seat and said cover member for movement between said valve seat and said cover member in 1. A sensing device for producing a fluid pressure signal on detection of application or removal of a thrust applied to the c. device, said device comprising:

a. a generally cylindrical body, a first coaxial bore extending from one end of said body to a first annular end face at an 5 response to a fluid-pressure differential between apinner end of said first bore, said first bore defining a conpropriate faces of said valve member to define a first p0siduit for connection to a source of fluid under pressure, a tion in which said valve member engages said valve seat second coaxial bore extending from an opposite end of to seal off said exhaust passage and a second position in said body to a second annular end face at an inner end of which said alve member is out of engagement with said said second bore, a central portion of said body dispos d valve seat, an area encompassed by said continuous seat between said first and second end faces, a coaxial cylinbeing greater than an area encompassed by said valve seat drical spigot extending from said second end face into 50 that i Valve m m r is mo able into engagement said second bore to an axial position adjacent aid op. with said valve seat in response IO a thrust provided by a posite end of said body, a third coaxial bore extending fluid Pressure the Same Side Of Said valve m r as h h id central b d portion f id fi d f said continuous seat which is less than the fluid pressure and through the length of said spigot, said third bore in Said exhaust Passage, Said Parabolic recess of Said defining an exhaust passage extending from said conduit, Cove! member Providing a cavity between Said Cover a valve seat in said body around the end of said exhaust member and Said Valve member adapted to enhance the passage remote f Said conduit at the end f Said Spigot pressure exerted on said valve member on the side of said adjacent said opposite end f said body, a coaxial counter cover member when a jet of fluid is directed at said orifice bore of enlarged diameter with respect to said second from Outside the devlce, said Valve member including a bore and extending from said opposite end of said body to Plate defining a disc acchmmodated as a loose fit in Said an axial position nearer said second end face than said counter bore which h Said y recess, valve seat, said coaxial counter bore defining a recess, at whereby when Sam eohdu connected 9 a source of fluid least one vent-opening communicating said second bore under Pressure and no threst PP to said Valve with an exterior of said body, member, the valve member is maintained out of engagea cover member secured to said opposite end of said body mem wl th h valve Seat by means meludmg the Pressure with said body recess extending between said valve seat fflu1 dSSumg e e exhaust P and when an P and said cover member, said cover member including a propnatethwst ePPhed to the "alvefhemeeri the Valve central orifice and a continuous annular seat around and merhber F urged engagement 531d Valve Seat concentric with said central orifice, a parabolic recess against fluld, preseure to off the exheust paseage concentric with Said orifice being provided on the Same so that achange in fluid pressure 111 the COlldUlL'COnSUIUI- side of said cover member as said continuous seat and exa fluld'pressure slgnal, Produced on 'P tending between said orifice and said continuous seat, mmauon ofathwst the Valve member said continuous seat being disposed adjacent to said body 

1. A sensing device for producing a fluid pressure signal on detection of application or removal of a thrust applied to the device, said device comprising: a. a generally cylindrical body, a first coaxial bore extending from one end of said body to a first annular end face at an inner end of said first bore, said first bore defining a conduit for connection to a source of fluid under pressure, a second coaxial bore extending from an opposite end of said body to a second annular end face at an inner end of said second bore, a central portion of said body disposed between said first and second end faces, a coaxial cylindrical spigot extending from said second end face into said second bore to an axial position adjacent said opposite end of said body, a third coaxial bore extending through said central body portion from said first end face and through the length of said spigot, said third bore defining an exhaust passage extending from said conduit, a valve seat in said body around the end of said exhaust passage remote from said conduit at the end of said spigot adjacent said opposite end of said body, a coaxial counter bore of enlarged diameter with respect to said second bore and extending from said opposite end of said body to an axial position nearer said second end face than said valve seat, said coaxial counter bore defining a recess, at least one vent-opening communicating said second bore with an exterior of said body, b. a cover member secured to said opposite end of said body with said body recess extending between said valve seat and said cover member, said cover member including a central orifice and a continuous annular seat around and concentric with said central orifice, a parabolic recess concentric with said orifIce being provided on the same side of said cover member as said continuous seat and extending between said orifice and said continuous seat, said continuous seat being disposed adjacent to said body recess and facing said valve seat, and c. a valve member captively disposed in said recess between said valve seat and said cover member for movement between said valve seat and said cover member in response to a fluidpressure differential between appropriate faces of said valve member to define a first position in which said valve member engages said valve seat to seal off said exhaust passage and a second position in which said valve member is out of engagement with said valve seat, an area encompassed by said continuous seat being greater than an area encompassed by said valve seat so that said valve member is movable into engagement with said valve seat in response to a thrust provided by a fluid pressure on the same side of said valve member as said continuous seat which is less than the fluid pressure in said exhaust passage, said parabolic recess of said cover member providing a cavity between said cover member and said valve member adapted to enhance the pressure exerted on said valve member on the side of said cover member when a jet of fluid is directed at said orifice from outside the device, said valve member including a plate defining a disc accommodated as a loose fit in said counter bore which constitutes said body recess, whereby when said conduit is connected to a source of fluid under pressure and no thrust is applied to said valve member, the valve member is maintained out of engagement with the valve seat by means including the pressure of fluid issuing from the exhaust passage, and when an appropriate thrust is applied to the valve member, the valve member is urged into engagement with said valve seat against said fluid pressure to seal off the exhaust passage so that a change in fluid pressure in the conduit, constituting a fluid-pressure signal, is produced on receipt or termination of a thrust on the valve member. 